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My friend just bought at auction a husqvarna zero turn ez4824 bf . Now at the time it would not run at all.
He asked me to have a look at it, however by the time I got round there, he had it fired up with a new battery and by passing the seat switch.
It runs drives stops all really nice, however when you pull up on the PTO switch to engage the blades, the engine dies. It does not bogg down like a stuck deck bearing, it is shut down fast like a safety switch.
The throttle control lever does not stay at max but when released moves back to 3/4 throttle, not sure if that is an issue. I am thinking reverse switch stuck on with one of the control levers, but I thought that would kill the blades not the engine. Whats your thoughts please?

The seat switch may have not been bypassed properly causing it to shut down when engaging blades. If you pull the kill wire off the coil it should bypass all the safety switches. If everything works without the kill wire hooked up then you have a safety switch or wiring issue.

Thank you I did not think of that

I did interupt the kill wire for the engine, see pictures. Now when the PTO/ Blade button is pulled up the engine stays running, but the blades still do not activate.
I know I am missing something obvious, should I just replace the seat switch, or is there another way I can get the blades to run ?

Forgot the pics. One is voltage regulator with the coil wires off to one side
One is the spade connector that I popped into the kill wire. When connected the engine dies as soon as the pto switch is used. When disconnected the engine continues to run as I pull the pto switch.

You will find the wiring diagram for the mower on the Husqvarna USA web site under the service section
The browser might keep sending you to the AUS web page which is about as much use as double sided dunny paper.
Download the manuals, owners & parts.
You will need the serial number to make sure you get the right one.
At the back of the owners manual you will see the wiring digram

Missing from the diagram is the starter motor & the engine connections
The box marked "engine pig tail" has 3 wires
Purple ( 12 V feed back to the battery
Grey +12 to the fuel solenoid
White, kill wire to the magneto.

The seat switch is a simple single contact and not needed to start the engine as the cranking circuit is the yellow wires.
The letters shown in the diagram are on the back of the switch
S=Start
M= magneto
G = ,Ground
A = Alternator
B= battery

Thank you, I got a copy of the manual with wiring diagram, it looks straight forward. But I cannot see why the blade pto being activated should be stopping the engine, or why with the engine ground cut the engine runs and the blades still will not.

Is there a way for me to tell if its being caused by the pto switch blue wire on the diagram still not activating the electric clutch which is the blade drive. Sorry for all the posts, I just feel bad when I say I will help, and I cant find an answer

If the switch is working you will get battery voltage on the purple wire with the switch off and nothing on the blue
Then when turned on you will see the blue wire now shows battery voltage
Somewhere near where the clutch wires go through the floor will be a 2 pin plug
Undo it and check for Battery voltage on the blue wire and ground on the black wire,
If you have that then the problem is in the clutch .
The wires tend to break off just where they enter the clutch because people do not tie the wire tight to the clutch ( including the factory ).

Taryl Fixes All shows how to fix a broken wire at the clutch with some self tappers on his U-Tube channel .

bertsmobile1 said:

If the switch is working you will get battery voltage on the purple wire with the switch off and nothing on the blue
Then when turned on you will see the blue wire now shows battery voltage
Somewhere near where the clutch wires go through the floor will be a 2 pin plug
Undo it and check for Battery voltage on the blue wire and ground on the black wire,
If you have that then the problem is in the clutch .
The wires tend to break off just where they enter the clutch because people do not tie the wire tight to the clutch ( including the factory ).

Taryl Fixes All shows how to fix a broken wire at the clutch with some self tappers on his U-Tube channel .

Click to expand...

Thankyou Bert, I appreciate the time you have taken, I will go rpund tomorrow and test.

When you go round, take a couple of fuses with you and replace the fuses on the mower
They suffer from weather and get quite corroded.
IF it turns out to be the clutch, search out a vendor who sells Prime Line parts,
They are the best value clutches but still not exactly cheap.
There are a couple of different clutches fitted to the EZ series & it looks to me that one of them is not a good fit as the pulleys rub on the clutch wires & cut through the insulation allowing the wires to short out everywhere.
One clutch has a pigtail which Taryl fixes in the video and the other has the wires plugging into the clutch itself.
The latter type are the ones that chaff and if I called them a moungrel to get at that would be too polite.
The plug has a catch on it which is almost impossible to get at once the clutch is fitted to the engine.
If you have a mirror on a stick, take that with you as well.

Looks like he needs a new switch, thanks again

They are a lot cheaper than the PTO clutch.

Yes indeed

Well I am afraid that I am back, sorry to say that when I fitted the new pto switch,, the engine still dies instantly when the pto switch is engaged.
I ran jumper wires from the battery to the PTO CLUTCH and it clicks quite strongly, so I believe the blade clutch is working.
I am a bit stck gentlement, time for a few beers and a head scratch!

Better for a cup of tea and some colouring in pencils.
Back to the first answer from MowLife, the seat switch is not by passed properly or the wiring is grounding.
When the PTO is pulled the brown wire from the seat & brake switches are connected to the magnet kill wire via the M terminal on the key switch.
IF either one of them has a ground contact the engine stops.
With yer bum in the seat, the seat switch wire should be open so there should be no ground from it.
With the brake off the brown wire from the PTO switch connects to the green wire from the M position on the key switch in a closed loop with no ground

So either the brake &/or seat switch is faulty and making a ground contact or the wires between them are pinched some where and making a ground contact
Pull the plug from the brake , seat & PTO switches
Check the double brown at the PTO switch for a ground.
IF you have one then the wires are shorting to the body somewhere
If not then the seat or brake switch is giving you a ground when it should not.
Connect the seat switch with yer bum in the seat check the double brown for ground.
If you have one the problem is in the seat switch
disconnect the seat switch & reconnect the brake switch.
With the brake off there should be no ground on that double brown.

I find it easier to understand if I manually jump the switch connections using some short wires with a spade on each end to emulate the switch in different positions.
However I always take the kill wire off the magneto just in case I accidentally jump 12V to the magneto which will kill it dead.

Thank you Thank you. I was starting to feel very bad cause I hadd said I would help him, and nothing I was doing helped.
With your help the mower deck now starts up just as soon as the pto button is pulled.
You made me look good folks and a decent bloke has a working mower.
Thanks